Wood is a common material used to construct doors and other architectural building elements. Even today, after the development of several new species of composite materials, wood remains one of the most widely-used structural materials because of its excellent strength and stiffness, pleasing aesthetics, good insulation properties and easy workability.
However, in recent years the cost of solid timber wood has increased dramatically as its supply shrinks due to the gradual depletion of old-growth and virgin forests. It is particularly expensive to manufacture doors from such material because typically less than half of harvested timber wood is converted to natural solid wood lumber, the remainder being discarded as scrap.
Accordingly, because of both the cost of high-grade timber wood as well as a heightened emphasis on conserving natural resources, wood-based alternatives to natural solid wood lumber have been developed that make more efficient use of harvested wood and reduce the amount of wood discarded as scrap. Plywood, particle board and oriented strand board (“OSB”) are examples of wood-based composite alternatives to natural solid wood lumber that have replaced natural solid wood lumber in many structural applications in the last seventy-five years. These wood-based composites not only use the available supply of timber wood more efficiently, but they can also be formed from lower-grade wood species, and even from wood wastes.
However, while the performance characteristics such as strength and insulation properties of these wood-based composites are comparable or superior to natural solid wood lumber, some users have complained that in certain high-moisture environments, such as exterior siding, the edges of the composite material experience swelling and cracking as water penetrates into the edges of the material and causes it to expand. To prevent this damage various techniques have been developed such as affixing metallic or polymeric moldings to the edges of the wood, or applying a polymer coating or film layer to the susceptible edges of the composite material. These techniques are effective to present edge swelling and cracking, but they have the disadvantage of greatly increasing the materials' cost and the complexity of the manufacturing process used to prepare it.
Given the foregoing, there is a continuing need for a wood composite material that can address these inadequacies. Notably this wood composite material would have superior or comparable performance to solid wood lumber while being lighter (lower density) than conventional OSB materials, have a better surface finish that would possibly, eliminate the need for a post-pressing sanding step, and have excellent resistance to edge-swelling and other such moisture-related defects. Additionally, this wood composite material would incorporate to some extent fibers harvested from tree species that are faster growing than those species which are conventionally used for wood composite materials.